You just had an opinion-editorial (op-ed) published in the Arizona Daily. The point of view aligns with an real-estate development position you are applying for in Hartford, Connecticut. Likely, those in Hartford receiving your cover letter haven't seen your op-ed.
No question, you should include in your cover letter a link to that. And, yes, the link should be what is inserted, not the whole piece presented as an attachment. No one likes to take the extra step of opening an attachment. In addition, attachments have been known to transmit viruses.
This recommendation to leverage links to give you an edge applies to all kinds of material. Those include:
- Announcements of awards you won or which you have been nominated for
- A post from your blog, on LinkedIn, or your Twitter account which has gone viral
- An article you contributed to which was published in a professional journal
- Your website
- Coverage of your public relations campaign for a client by the media.
But, first you have to check if the link is still active. Several years ago, I published over 140 analyses of public companies on Motley Fool. Those are no longer live links. Listing a dead link screams that you are not paying attention.